Punch press



Y Nov. 27, 1951 w. L. ALLlsoN 2,576,328

PUNCH PRESS Filed Sept. 10, 17949 FOOT OPERATED VALVE 53 akM/j/ (62A (5256 sa s (54 64;. 42) 47 6 [44 {41(.39 37) Y- l. Q .n l J 53 :5i 62 50521 :L /6.4. 60 y i 2, l F 1 l/ .l 23 /5/ Q1 l||| u .'l'szt- (a *alf v58/ la L42 AT TORNEY Patented Nov. 27, 1951 UNITEDg 4STATes rATsNToFFlcs,

William L. Allisonlhoenix, Ariz., assignor to v AllisonSteeVManufacturing Company, Phoeniin'Ariz.',"a company of ArizonaApplication September 10, 1949, Serial No. 114,999

3 Claims.. (Cl. 164-104) 'This invention relates to improvements a punchpress and more particularly` provides improvements in a, punch presswith a continuously oscillating head.

In a punch press ofthe oscillating type, the head suspended above astationary table continually moves up and down transverse ,to the table.A punch holderis slidably disposed in the oscillating head with a punchcoupled to its lower end. The punch in this oating position lightlyimpinges the surface of a work piece on the table but does not pierceit. When the punch in the floating position strikes the work, the punchand holder will move upwardly with respect to the head. If the punch isto pierce the work, the holder must be locked to the head. In the priorart, this is accomplished by moving manually a locking piece or plungerinto -a free space above the punch holder. The punch on the nextdownward stroke pierces the work on, the

table.

An operator using the manual locking mechanism must ltime insertion ofthe plunger'or locking piece with the stroke of the press. Manualoperation is slow, and frequently the plunger will be engaged onlypartially. l That is, the lower face of the plunger will cover only partof the upper vend of the holder before the punchstrikes the work. Inconsequence, thereis excessive wear on holder and plunger and notinfrequently, a

broken part. i

To remedy the shortcomings of the manually operated plunger, the plungerof my apparatus is actuated pneumatically. For that matter, the plungermay be actuated by any compressed fluid, liquid or gas. Hereinafter, the,term pneumatic is used to describe all such fluid-actuated means. Thispneumatically actuated plunger is much faster and hence, more certain tocover completely the top surface of the punch holder. For this reason,wear and breakage are greatly reduced. In the preferred form of mydevice, the operator need not remove a hand from the work piece toactuate the plunger, because a foot pedal is utilized to control an airvalve that actuates the plunger. This results in a safer punch press.

Furthermore, with the use of my pneumatically actuated plunger, thenumber of stroke cycles per minute may be increased because theengagement of the plunger is dependent no longer upon manual operationwhich is necessarily slow. Hence, my invention results not only in animproved means of engagement but also in more rapid operation.

In a presently preferred form of my apparatus,

amember oscillates transversely to a table upon which the work is laid..A punch or punch holder is disposed in the member and arranged to slidetransversely to the table. If the punch holder is utilized, the punch isattached to the holders end. Means pneumatically actuated lock the punchor punch holder to the oscillating member when the punch is to piercethe work. Means are provided for releasing the punch or punch holderfrom the locked position after the punching operation has beencompleted. y

These and other aspects of my invention will be understood morethoroughly in light of the following detailed description, taken inconjuncftion with the accompanying drawings in which; Fig. 1- is afragmentary front elevation of a presently preferred form of myapparatus; v

Fig. 2 is a side elevation of the apparatus of Fig. 1 as viewed from thesection line 2-2 of Fig. 1;

Fig. 3 is a front elevation, partly insection, taken along line 3-3 .ofFig. 2 and showing the punch piercing the work; and 'Y Fig. 4 is a topplan View along line 4-4 of Fig. 3.

As illustrated in Figs. 1 and 2, a body I 2 is attached to the undersurface of a cross head I3 by bolts I5, I Ii, the heads of which areslid into a pair of T-shaped grooves I'I in the cross head. An aircylinder housing I8 is fastened to the body parallel to the undersurface of the cross head by four set screws I9. A punch holder 2l iscarried in a slidable, upright position in Vthe body. A coaxial punch 22is fastened to the lower end of the holder by a coupling nut 23. .I

A table 25 below the cross head supports the work. A plate 21 isfastened to the table by a pair of bolts 28, 29, the heads lof which areslid into T-shaped grooves 30 in the table. An annular bushing 33 withits bore 34 in alignment with the punch is mounted in a cylindricalrecess 35 of the plate. The bore of the bushing receives the punch afterit has pierced the work.

In Fig. 3, an air port 3l in the end of the air cylinder housing isconnected by a hose 38 (see Fig. 1) to a source `of compressed airthrough a foot operated valve 63. The air port opens into a horizontalbore 39. A piston 4I slidably disposed in the bore is press fitted overone end of a plunger shaft 42. The piston abuts against a Verticalshoulder of a swollen section 44 of the shaft. A helical spring 46coaxial with the shaft is placed between the other shoulder of theswollen section and a vertical face 41 of the body member.

The plunger is substantially a rectangular block with its lower facepartially cut awayjto Y permit movement of the plunger over arectangular head 55 of the punch holderewhich projects upwardly into thecavity. A slot 58 inthe 'central portion of the plunger (see Fig. 4)permits the plunger to move along its path, even -thouglri the bolt IGwhich fastens the body to the cross head extends vertically l.throughthe cavity and plunger.

JThe punch holder is cylindrical and is 1slidably held ina Vertical bore60 of V'the body by its rectangular head 55, which normally rests on thefloor of the cavity. The -corner 62 or the head adjoining 4the lowerface of the plunger is rounded to provide smoother operation. Similarlythe 'corner 62A of the plunger 52, which contacts the cornercf the head,is rounded.

Whenever the punch press is in operation, the cross head andthe membersattached thereto will oscillate up and dow-n above the work on thetable. As long as the space above the head of the punch holder is clear(i. e. when -the plunger is in its far right position as shown by dottedlines 63, `64 in Fig. 3), the punch Will strike the work lightly. Whenthe `guide mark on the work is in alignment with the point of the punch,the foot-operated valve is actuated by the operator and vair 'underpressure is forced into the bore through the air port, moving thepiston, shaft, .y

and `plunger to the far left A(as illustrated in Fig. 3). Then theplunger occupies the former free space above the punch holder, and thepunch on the next downward stroke will penetrate the work.

When the operator removes his foot from the foot valve, the air escapesand the helical spring returns the piston, shaft, and plunger to theunengaged position as indicated by the dotted lines in Fig. 3.

It is to lbe understood that the form 'of my invention, herein describedand illustrated, is a preferred embodiment and that various changes maybe resorted to without departing from the Yspirit of my invention, orscope of the claims. For example, the helical spring could be'eliminatedand the plunger pneumatically actuated in both directions.

I claim:

1. In a punch press of the continuously oscillating type and including atable, a cross head oscillatable perpendicularly to the table, thecombination comprising a body member affixed to the lower end of thecross head and having an 'elongated cavity extending transversely of theaxis of oscillation and opening against the bottom 'face of the crosshead, a bore in the bottom of said body member opening into said cavityadjacent an end thereof, a punch slidably mounted through said bore andhaving on its inner end an enlarged head of .larger diameter than saidbore, a 'gag slidably mounted in said cavity, the gag being shorter thansaid cavity but of substantially the same cross section and having anotch in the lbottom thereof extending from its inner end to form anoverhanging projection insertable `between the bottom of said .crosshead and .the top surface .of said .enlarged head to ll .the spacetherebetween, hydraulic means for displacing said gag in the directionof said enlarged head, spring .means for retracting the gag, and a footoperatedY valve forcontrolling .the loperation .of ysaid hydraulicmeans. Y

2. Apparatus according tto claim 1 wherein Athe :gag has Ialongitudinally elongated slot centrally -spaced between its sides andextending through thegag from top Lto bottom and the body member isaffixed to the cross head .by a bolt .passing through the `said slot invthe gag, the vgag being vfree .to .oscillate longitudinally through adisplacement defined by the longitudinal .elongation of said slot.

3. Apparatus according to claim 1 wherein said enlarged head .of .thepunch is rounded along the .edge directed .toward said gag and the outer1ow- .er edge of the overhanging projection .of 4said gag is rounded,the arrangement being such `that the edge of the head Vand theroundededge of the -gag 4engage as the gag is .displaced towards thehead. Y

WILLIAM L. ALLISON.

REFERENCES CITED The following references are of record in the file ofthis patent: v

UNITED STATES PATENTS Number Name .Date

627,153 Tennant June 2.0, 1899 1,557,385 Tastenhoye Oct. 13., 19251,856,175 Towle May :3, 19.32

